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Grant Grasshopper Calculating Machine

Description

This commercially sold example of George B. Grant’s grasshopper calculating machine at one time belonged to tabulating machine inventor Herman Hollerith Jr. of Washington, D.C.

The lever-set manually operated non-printing connection pawl machine has an open iron frame painted black, with steel and brass parts and paper labels. Five pins at the front of the machine slide horizontally to set numbers. Next to each pin is a thin strip of paper with the digits from 0 to 9 printed on it, the digits increasing toward the back of the machine. Each strip also has complementary digits in smaller type, for use in subtraction and division. Moving a pin back drives back a toothed rack.

Behind the racks is a movable carriage that slides to six different positions and has 11 gears on it. A paper strip with digits on it is next to each gear. Turning a crank at the front right of the machine moves the racks back to engage the gears, turning each one of them in proportion to the number set. When the adding frame reaches the end of its backward movement, a cam set on the crank shaft at the front raises all the register gears a little so that the gears are disengaged from the racks and not moved in the return motion.

One tooth on each gear extends so that when the gear has made a complete rotation, it engages one of the carry teeth arranged on a spiral shaft above the carriage. As the adding racks return to position, the shaft revolves and the carry tooth pushes the next gear up by one, resulting in a carry. Releasing the carriage and turning it one revolution zeros the result shaft.

A paper tag to the right of the pins reads: GRANT CALCULATING MACHINE COMPANY [/] BOSTON, PHILADELPHIA, CLEVELAND. Two windows at the front of the machine read: C B.

Compare MA*310647 and MA*335633 (MA*310647 has a metal plate at the back not found on MA*335633).

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